As is quite well known in the railway art, to which the present invention applies, railway cars are normally connected to one another by an arrangement consisting of coupler members to form a train consist. Such coupler members may be a conventional-type coupler which is backed by a draft gear assembly to control the slack between such railway cars during operation of the train consist. Or, as is the more recent case in the railway industry, such cars may be joined together by a slackless drawbar arrangement. In general, however, couplers used in this application have consisted of an independent unit that is secured to each end of a railway car in a position to allow interconnection with another independent unit of an adjacent car thereby forming the connection between the adjacent cars. On the other hand, the slackless drawbar arrangements in use are normally an integral-type coupling unit which extend between the ends of a pair of adjacent cars from the connection required between such pair of cars.
At the present time, regardless of the type of coupling arrangement being used, a shank end portion of the coupler member or slackless drawbar will be positioned in a manner such that it extends into the center sill portion of such railway car. In this position, the shank end portion is anchored so that during operation of the train consist the longitudinal forces generated by such operation will be transmitted to such railway car.
The present invention is primarily directed to an improvement in an articulated spherical connector apparatus which has application in a slackless-type drawbar coupling arrangement. In such a slackless coupling arrangement, as is well known in the railway car coupling art, the drawbar, or coupler, includes a portion that is positioned within the center sill portion of a car in a manner such that the longitudinal play or other undesirable movements associated with the coupling arrangement can be maintained at a minimum. However, because successive railway cars in a train consist normally must accommodate at least some amount of relative movement between such cars, particularly when both curved portions and inclined portions of the track must be negotiated during operation of such consist, there must be some provision in the coupling arrangement which allows each car to move in each of a pitch, a yaw and a roll mode which will be encountered with respect to such coupler arrangement. Additionally, it is obvious that, in any type coupling system which is used to form a connection between a pair of adjacent railway cars, there must be some provision made which permits such connected railway cars to be disconnected as required.
In a slackless-type coupling system, the coupler member is generally secured in such a manner that any undesirable longitudinal movement of such member in relationship to the car body portion will be either eliminated or at least substantially minimized. In the various coupling arrangements that have been taught in the prior art, this has been accomplished usually through the provision of a tapered wedge member that is located in the arrangement between a rear wall of the pocket casting and a follower block member which is positioned to rest against the butt end of the coupler member. Normally, the pocket casting in these prior-art-type coupling systems will be secured to the railway car in the center sill portion of such car. The wedge member provided tends to force the follower block away from the pocket casting end wall and into a substantially firm engagement with the butt end of the shank of the coupler member during operation of the train consist. For example, when such cars are being pushed by a locomotive, the longitudinal forces that are generated on this type coupling arrangement will cause a compression of the coupler member against the follower block, the wedge member and the end wall of the pocket casting to occur.
On the other hand, when such cars are being pulled by the locomotive, the longitudinal forces that are being generated on such coupling arrangement will exhibit a tendency to separate the drawbar member from the pocket casting. These forces are countered in these coupling arrangements by a draft key member. This draft key member is a metal bar which extends laterally of the center sill portion of the car through axially-opposed slots provided in the side walls of such center sill and through a slot provided in the shank portion of the coupler member. Normally, in a slackless-type coupling arrangement, the drawbar member is held tightly in position between the draft key bearing block and/or the draft key member and the follower block. This is usually accomplished by operation of the wedge member which separates the pocket casting and the follower block and compresses such follower block against the drawbar member. This compression of the follower block against the drawbar member forces the drawbar member against the draft key bearing block and/or the draft key member. Generally, however, the engageable mating faces of both the follower block and the drawbar member will include a curved surface which permits the drawbar member to pivot slightly over a limited range in both a vertical direction and a lateral direction. The curved surfaces of the mating faces also permit the car to roll with respect to the drawbar member during operation of the train consist. In addition, the drawbar member normally pivots at the draft key member or an arcuate draft key bearing block which is interposed between the components.
In the pocket casting of the slackless-type drawbar coupling arrangement in use at the present time in the railroad industry, the top, bottom and vertically disposed side walls provide a cavity for receiving therein the follower block member and the wedge member. In this coupling arrangement, the side walls of such pocket casting normally will limit the translation and, consequently, the rotation of the follower block member about the vertical axis of the arcuately-shaped butt end portion of the drawbar member in the event of a horizontal angling of the drawbar member occurring during operation. It is generally well recognized that such rotation of the follower block member can cause the wedge member to rotate in an undesirable manner about the longitudinal axis of the car body. This undesirable rotation can possibly result in such wedge member becoming hung up between the vertical side walls of the pocket casting thereby leading to substandard performance of the coupling arrangement. This can especially happen, for example, when the wedge member is relatively small in height in relation to its width. One of the most commonly used methods being used for controlling such rotation of the follower block member as well as the relative orientation between the wedge member and such follower block member is to provide an extremely close tolerance between such vertical side walls of the pocket casting and the wedge member and the side surfaces of such follower block member. As would generally be expected, however, because of the cast nature of a number of these component parts this particular procedure being used will normally require a rather large amount of uneconomical tolerance design and machining of finished component parts.
Furthermore, in more recent times, the railroad industry has discovered that the connection of a number of cars together to form a semi-permanent unit can be advantageous for a number of reasons. For example, railroad cars that are particularly adapted for "piggyback" service have been connected together in such semi-permanent manner. These units are commonly known in the railroad industry as a "ten-pack." These semi-permanent units do not require the use of the standard coupling arrangement except between units since each semi-permanent unit needs to be only broken on occasion to permit maintenance of various individual components as necessary. Therefore, in this semi-permanent unit arrangement, one standard railway car truck may be used to support the end of two adjacent car bodies.
Generally, an articulating device will be used to combine railroad cars into these semi-permanent units. Such a device includes a male and a female connecting member which have ends that are attached respectively to adjacent ends of the railway car bodies forming such semi-permanent unit. A pin member is disposed in aligned apertures formed in the outer end of such member to form a joint therebetween. To allow for both vertical and horizontal movements that are required between male and female members during operation of the semi-permanent units, the pin aperture in the male member is somewhat larger than the pin member and includes a rear surface portion which provides a substantial contact area with such pin member. In order to maintain the pin aperture and the pin member in a desired controlled slack relationship, the male member is urged forward by a follower member which is carried within the female member and engages an end surface of the male member. In turn, the position of the follower member can be regulated, as required, by a wedge element which engages a pair of resilient components that are carried by the follower member in this articulated coupling arrangement.
Some examples of the prior art coupling arrangements that have been discussed briefly above are shown in U.S. Pat. Nos. 4,129,219; 4,258,628; 4,456,133; 4,593,827; 4,593,829 and 4,700,853.